Plastic compositions containing poly(phenylene oxide) and a bis-phenoxy flame retardant

ABSTRACT

Plastic compositions containing poly(phenylene oxide) and bis-phenoxy compounds having the formula ##SPC1## 
     Wherein Z is bromine or chlorine, m and m&#39; are integers having a value of 1-5, i and i&#39; are integers having a value of 0-2, HBCA is a halo-branched chain alkylene group having from 1 to 6 carbon atoms and A is cyano, nitro, lower alkoxy, lower alkyl, fluorine, dialkylamino, phenyl, halo-phenyl, benzyl or halo-benzyl.

This application is a continuation-in-part of copending application Ser.No. 260,240, filed June 6, 1972 and now abandoned. The entirespecification of this case, Ser. No. 260,240, is to be considered asincorporated herein by reference.

The prior art considered in conjunction with the preparation of thisapplication is as follows: U.S. Pat. No. 2,130,990; U.S. Pat. No.2,186,367; U.S. Pat. No. 2,329,033; U.S. Pat. No. 3,666,692; U.S. Pat.No. 3,686,320; U.S. Pat. No. 3,658,634; German Pat. No. 1,139,639;German Pat. No. 2,054,522; Japanese Pat. No. (72) 14,500 as cited inVolume 77, Chemical Abstracts, column 153737k (1972); ChemicalAbstracts, Volume 13, column 448⁵ ; Chemical Abstracts, Volume 31,column 7045⁹ ; and Journal of the Chemical Society, pages 2972-2976(1963). All of these publications are to be considered as incorporatedherein by reference.

The present invention relates to plastic compositions containingpoly(phenylene oxide), (herein referred to as PPO), and certainbis-phenoxy compounds (hereinafter defined) as flame retardants for saidplastic compositions.

PPO plastics and utility thereof are known in the art as exemplified byEncyclopedia of Polymer Science and Technology Vol. 10, pages 92-111,John Wiley & Sons, Inc., New York, 1969 and which publication is in totoincorporated herein by reference.

The need for flame retarding PPO plastics has also been recognized inthe art as exemplified by Encyclopedia of Polymer Science andTechnology, ibid, pages 100 and 103.

The resultant disadvantages in the utilization of various prior artmaterials as flame retardants for PPO include, without limitation,factors such as thermal migration, heat instability, light instability,non-biodegradable, toxicity, discoloration and the large amountsemployed in order to be effective. Thus, there is always a demand for amaterial which will function as a flame retardant in poly(phenyleneoxides) and concurrently will not, by incorporation therein, adverselyeffect the chemical and/or physical and/or mechanical properties of theresultant poly(phenylene oxide) plastic composition.

The prior art problem of providing a flame retarded poly(phenyleneoxide) composition having desired chemical, physical and mechanicalproperties has now been substantially solved by the present inventionand the above-described disadvantages substantially overcome.

Accordingly, one of the main objects of the present invention is toprovide poly(phenylene oxide) plastic compositions which are flameretarded.

Another object of the present invention is to provide a material forpoly(phenylene oxide) plastic compositions which will not substantiallyadversely effect the chemical and/or physical and/or mechanicalproperties of said compositions.

A further object of the present invention is to provide a flameretardant which is economic and easy to incorporate into poly(phenyleneoxide) plastics without being degraded or decomposed as a result ofblending or processing operations.

It has been found that the foregoing objects can be obtained by theincorporation of a new class of bis-phenoxy compounds in PPO tosubsequently provide flame retarded compositions which exhibitoutstanding chemical, physical and mechanical properties.

The bis-phenoxy compounds used in the present invention compositionshave the formula: ##SPC2##

In Formula I above, Z is bromine or chlorine; m and m' are integers eachindependently having a value of 1-5; i and i' are integers eachindependently having a value of 0-2; HBCA is a halo-branched chainalkylene group having from 1 to 6 carbon atoms (e.g. CH₂ C(CH₂ Cl)H; CH₂C(CH₂ Cl)₂ ; CH₂ CH₂ C(CH₂ Br)H; and CH₂ C(CH₂ Cl)HCH₂); and A is fromthe group, cyano (--CN), nitro (--NO₂), lower alkoxy (e.g. --OCH₃, OC₂H₅), lower alkyl (e.g. CH₃, C₂ H₅, C₃ H₇, C₄ H₉), fluorine, dialkylaminoe.g. --N(CH₃)₂ --N(C₂ H₅)₂, phenyl (--C₆ H₅), halo-phenyl, benzyl (--CH₂C₆ H₅), and halo-benzyl.

In Formula I, the sum of i + m or i' + m' is not greater than 5.

It is to be understood that all of the compounds falling within theabove Formula I and as heretofore defined are generically describedherein as "bis-phenoxy" compounds.

Illustrative (but without limitation) of some of the present inventionbis-phenoxy compounds are shown below: ##SPC3##

the exemplary definition of A, Z, i, i', m, m' and HBCA are listed inTable I.

                                      Table I                                     __________________________________________________________________________    Compound No.                                                                          Z m m'                                                                              A       i i'  HBCA                                              __________________________________________________________________________    1       Br                                                                              3 3 --      0 0 CH.sub.2 C(CH.sub.2 Cl)H                            2       Br                                                                              3 3 --      0 0 CH.sub.2 C(CH.sub.2 Cl).sub.2                       3       Br                                                                              5 5 --      0 0 CH.sub.2 C(CH.sub.2 Cl)H                            4       Br                                                                              2 2 --CN    1 1 CH.sub.2 CH.sub.2 C(CH.sub.2 Br)H                   5       Br                                                                              2 2 --NO.sub.2                                                                            1 1 CH.sub.2 C(CHCl.sub.2)H                             6       Cl                                                                              2 2 --OCH.sub.3                                                                           1 1 CH.sub.2 C(CH.sub.2 Cl)H                            7       Br                                                                              3 3 --OCH.sub.3                                                                           1 1 (CH.sub.2).sub.3 C(CH.sub.2 Cl).sub.2               8       Br                                                                              2 2 --CH.sub.3                                                                            1 1 CH.sub.2 C(CH.sub.2 Cl)H                            9       Br                                                                              2 2 F       1 1 CH.sub.2 C(CH.sub.2 Cl).sub.2                       10      Br                                                                              2 2 --N(CH.sub.3).sub.2                                                                   1 1 CH.sub.2 C(CHBr.sub.2)H                             11      Br                                                                              2 2 --C.sub.6 H.sub.5                                                                     1 1 (CH.sub.2).sub.2 C(CBr.sub.3)H                      12      Cl                                                                              2 2 --C.sub.6 H.sub. 3 Br.sub.2                                                           1 1 CH.sub.2 C(CH.sub.2 Cl)H                            13      Br                                                                              2 2 --CH.sub.2 C.sub.6 H.sub.5                                                            1 1 CH.sub.2 C(CCl.sub.3).sub.2                         14      Br                                                                              2 2 --CH.sub.2 C.sub.6 H.sub.3 Br.sub.2                                                   1 1 CH.sub.2 C(CH.sub.2 Cl)H                            15      Cl                                                                              3 3 --C.sub.6 H.sub.3 Cl.sub.2                                                            1 1 CH.sub.2 C(CH.sub.2 Cl)H                            16      Br                                                                              3 3 F       1 1 CH.sub.2 C(CCl.sub.3).sub.2                         17      Cl                                                                              5 5 --      0 0 CH.sub.2 C(CH.sub.2 Cl)H                            18      Br                                                                              4 4 --      0 0 CH.sub.2 C(CH.sub.2 Cl)H                            19      Br                                                                              3 3 --C.sub.6 H.sub.2 Br.sub.3                                                            1 1 (CH.sub.2).sub.3 C(CH.sub.2 Cl).sub.2               20      Br                                                                              3 3 --      0 0 CH.sub.2 C(CH.sub.2 Cl)HCH.sub.2                    21      Br                                                                              2 2 --      0 0 CH.sub.2 C(CCl.sub.3)H                              22      Br                                                                              4 4 --      0 0 CH.sub.2 C(CHBr.sub.2)H                             23      Br                                                                              3 3 F       2 2 CH.sub.2 C(CH.sub.2 Cl)H                            24      Br                                                                              1 1 --C.sub.4 H.sub.9                                                                     1 1 CH.sub.2 C(CH.sub.2 Cl)H                            25      Br                                                                              1 1 -- OC.sub.4 H.sub.9                                                                   1 1 (CH.sub.2).sub.3 C(CH.sub.2 Cl)H                    __________________________________________________________________________

In general, the bis-phenoxy compounds are prepared by first reacting ahalogenated phenol with a halogenated alkanol at elevated temperaturesin the presence of a basic material such as alkali metal hydroxides,carbonates, bicarbonates, oxides and hydrides to form an intermediateproduct. The preferred alkali metals are potassium and sodium. Where onedesires to increase, for example, ease of handling the intermediatereaction mass, solvents such as ketones (e.g. acetone, methyl ethylketone, and methyl iso-butyl ketone), alcohols (e.g. methanol, ethanol,iso-propyl alcohol, butyl alcohol and glycols), or aqueous solvents(e.g. water, a mixture of water and alcohol and a mixture of water andketone) can be employed. The intermediate product is separated from thefirst reaction medium via, for example, filtration. This product is thencontacted with a halogenating agent such as SOCl₂, PCl₃, PCl₅, PBr₃,PBr₅, (C₆ H₅)₃ PBr₂ and the like. Preferably this second step is carriedout in a reaction medium such as an aromatic solvent. The desired endproduct i.e. the bis-phenoxy compound, can be recovered from thereaction mass via various methods such as distillation orcrystallization. Where the end product requires recovery viacrystallization, the aromatic solvent containing the halogenating agentis, for example, benzene, toluene, xylene, dichlorobenzene and the like.

Specifically, the bis-phenoxy compounds are prepared according to thefollowing reactions: ##SPC4##

In the above reaction, X is halogen, preferably chlorine and R is analkylene having C₃ -C₆. Where m and m' and i and i' are differentintegers, then equivalent molar portions of the particular halogenatedphenol are used with equivalent portions of dissimilar halogenatedphenol.

The above reaction is conducted at temperatures ranging from thefreezing point of the initial reaction mass to the boiling pointthereof. Preferably the temperatures are from about 40° to about 200° Cand more preferably from about 50° to about 175° C. It is to beunderstood that the reaction can be conducted under sub-atmospheric(e.g. 1/10-8/10 atmospheres), atmospheric or super-atmospheric (e.g.1.5-10 atmospheres) pressure. Preferably, the reaction is carried out atatmospheric pressure.

The above-described processes can be carried out with conventional,readily available chemical processing equipment. For example, aconventional glass-lined vessel provided with heat transfer means, areflux condenser and a mechanical stirrer can be advantageously utilizedin practicing any of the preferred embodiments of the inventiondescribed in the examples set forth herein.

The amount of bis-phenoxy compound employed in the present inventioncompositions is any quantity which will effectively render thepoly(phenylene oxide) containing composition flame retardant. Ingeneral, the amount used is from about 1 to 25% by weight, based on thetotal weight of the composition. Preferably, the amount employed is fromabout 5 to about 20% by weight. It is to be understood that any amountcan be used as long as it does not substantially adversely effect thechemical and/or physical and/or mechanical properties of the end polymercomposition. The amount utilized, however, is such amount which achievesthe objectives described herein.

It is to be understood that the term poly(phenylene oxide) as usedherein means products of the oxidative polymerization of phenols topoly(oxy phenylenes) which are also known as poly(phenylene oxides) orpoly(phenylene ethers). This term also includes blends with otherthermoplastics and/or plasticizers, however, the poly(phenylene oxide)comprises in all cases at least 50% by weight of the blend.

Thus the poly(phenylene oxide) used in the present inventioncompositions is any poly(phenylene oxide) herein defined and which oneso desires to flame retard. It is to be understood that thepoly(phenylene oxide) used can be a "virgin" material, i.e.substantially free of additives such as stabilizers, plasticizers, dyes,pigments, fillers, and the like, or the poly(phenylene oxide) can haveadditives (such as those mentioned and described herein) alreadycontained therein or added concurrently with or after the addition ofthe bis-phenoxy compounds.

Another facet of the present invention relates to the use of certainmetal compounds with the bis-phenoxy compounds to promote a cooperativeeffect therebetween and thus enhance the flame retardancy of theresultant plastic composition as compared to the flame retardancy ofeither one component used separately. These "enhancing agents" are fromthe group antimony, arsenic, bismuth, tin and zinc-containing compounds.Without limitation, examples of said enhancing agents include Sb₂ O₃,SbCl₃, SbBr₃, SbI₃, SbOCl, As₂ O₃, As₂ O₅, ZnBO₄, BaB₂ O₄.H₂ O,2.ZnO.3B₂ O₃.3.5H₂ O and stannous oxide hydrate. The preferred enhancingagent is antimony trioxide.

The amount of enhancing agent employed in the present inventioncompositions is any amount which when used with said bis-phenoxycompounds will promote a cooperative effect therebetwen. In general, theamount employed is from about 1 to about 15%, preferably from about 2 toabout 10%, by weight, based on the total weight of plastic composition.Higher amounts can be used as long as the desired end result isachieved.

It is also within the scope of the present invention to employ othermaterials in the present invention compositions where one so desires toachieve a particular end result. Such materials include, withoutlimitation, adhesion promotors; antioxidants; antistatic agents;antimicrobials; colorants; flame retardants such as those listed onpages 456-458, Modern Plastics Encyclopedia, ibid, (in addition to thenew class of flame retardants described herein); heat stabilizers; lightstabilizers; pigments; plasticizers; preservatives; ultravioletstabilizers and fillers.

In this latter category, i.e. fillers, there can be mentioned withoutlimitation, materials such as glass; carbon; cellulosic fillers (woodflour, cork and shell flour); calcium carbonate (chalk, limestone, andprecipitated calcium carbonate); metal flakes; metallic oxides(aluminum, beryllium oxide and magnesia); metallic powders (aluminum,bronze, lead, stainless steel and zinc); polymers (comminuted polymersand elastomer-plastic blends); silica products (diatomaceous earth,novaculite, quartz, sand, tripoli, fumed colloidal silica, silicaaerogel, wet process silica); silicates (asbestos, kaolimite, mica,nepheline syenite, talc, wollastonite, aluminum silicate and calciumsilicate); and inorganic compounds such as barium ferrite, bariumsulfate, molybdenum disulfide and silicon carbide.

The above mentioned materials, including fillers, are more fullydescribed in Modern Plastics Encyclopedia, ibid, and which publicationis incorporated herein (in toto) by reference.

The amount of the above described materials employed in the presentinvention compositions can be any quantity which will not substantiallyadversely effect the desired results derived from the present inventioncompositions. Thus, the amount used can be zero (0) percent, based onthe total weight of the composition, up to that percent at which thecomposition can still be classified as a plastic. In general, suchamount will be from about 0 to about 75% and specifically from about 1to about 50%.

The bis-phenoxy compounds can be incorporated in to the poly(phenyleneoxide) at any processing stage in order to prepare the present inventioncompositions. In general, this is undertaken prior to fabrication eitherby physical blending or during the process of forming poly(phenyleneoxide) per se. Where one so desires, the bis-phenoxy compounds may bemicronized into finely divided particles prior to incorporation into thepoly(phenylene oxide).

EXAMPLE I

A poly(phenylene oxide) (PPO) plastic material, (GE 534-801, a productof General Electric Company and containing substantially no fillers) isutilized as the base resin in order to prepare 26 formulations (plasticcompositions). With the exception of formulation No. 1, the particularbis-phenoxy compound (and the antimony trioxide enhancing agent whereindicated) is incorporated into the plastic by adding both to aBrabender mixer ("Plastic-Corder", Torque Rheometer, Model PLV-150, C.W. Brabender Instruments Inc., South Hackensack, N.J.). The mixer isequipped with a pair of roller type blades positioned within a headprovided with heat transfer means.

The resultant mixture is heated to about 320° C.; at this temperature,it is in a molten state. The percentages by weight of each componentutilized in the respective formulations are listed in Table II. Eachformulation is discharged from the mixer and upon cooling solidifies andis ground into chips. The chips are subjected to compression molding ina Wabash press by placing said chips between two platens, the bottom ofwhich contains four equal size depressions 3 inches by 5 inches by 1/8inch deep. The top platen is then placed over the bottom platen and heattransfer means supplied thereto in order to melt said chips and thusprovide solid samples (after cooling) for testing.

Portions of the samples of each respective formulation (Nos. 1-26)prepared according to the above described procedure are then subjectedto two different standard flammability tests, i.e. UL 94 and ASTMD-2863-70. The UL 94 is, in general, the application of a burner to atest specimen (strip) for a certain period of time and observation ofcombustion, burning, and extinguishment. This procedure is fully setforth in Underwriters' Laboratories bulletin entitled UL 94, Standardfor Safety, First Edition, Sept. 1972 and which is incorporated hereinby reference. ASTM No. D-2863-70 is a flammability test which correlatesto flammability of a plastic specimen to the available oxygen in itsimmediate environment; this correlation is stated as an Oxygen Index,O.I., level predicated upon the percent oxygen in the gaseous mediumwhich is required to just provide a steady state of continuous burningof the plastic specimen. This ASTM method is fully described in 1971Annual Book of ASTM Standards -- Part 27, published by the AmericanSociety For Testing and Materials, 1916 Race Street, Philadelphia, Pa.;this publication is to be considered as incorporated (in toto) herein byreference.

The results of these flammability tests are shown in Table II.

                                      TABLE II                                    __________________________________________________________________________    FLAMMABILITY DATA FOR PPO PLASTIC COMPOSITIONS                                CONTAINING BIS-PHENOXY COMPOUNDS                                              FORMULATION                                                                            BIS-PHENOXY                                                                           COMPOUND                                                                             ENHANCING AGENT                                                                          OXYGEN INDEX                                                                           UL 94                             NO.      NO.     %      Sb.sub.2 O.sub.3, %                                                                      %                                          __________________________________________________________________________    1.       --       0     0          25.5     SB                                2.       1       20     0          27.5     SE-2                              3.       1       20     10         34.5     SE-0                              4.       3       20     0          28.5     SE-1                              5.       3       20     10         38.0     SE-0                              6.       4       20     0          26.5     SE-2                              7.       4       20     10         31.0     SE-0                              8.       5       20     0          27.5     SE-2                              9.       5       20     10         34.0     SE-0                              10.      6       20     0          27.0     SE-2                              11.      6       20     10         30.5     SE-0                              12.      8       20     0          28.0     SE-1                              13.      8       20     10         34.5     SE-0                              14.      12      20     0          27.5     SE-2                              15.      12      20     10         36.0     SE-0                              16.      14      20     0          29.5     SE-0                              17.      14      20     10         39.0     SE-0                              18.      16      20     0          28.5     SE-1                              19.      16      20     10         37.5     SE-0                              20.      17      20     0          29.0     SE-0                              21.      17      20     10         36.0     SE-0                              22.      20      20     0          28.5     SE-1                              23.      20      20     10         37.5     SE-0                              24.      23      20     0          27.0     SE-2                              25.      23      20     10         34.0     SE-0                              26.      25      20     10         33.5     SE-0                              __________________________________________________________________________

Referring to Table II, the bis-phenoxy compound number relates to thestructural formulae heretofor set forth in Table I; a difference of 2%in the Oxygen Index values is considered significant; and the UL 94values are on a graduated scale wherein the highest degree to lowestdegree of flame retardancy is respectively SE-0, SE-1, SE-2, SB andBurns.

The results shown in Table II demonstrate the unique effectiveness ofthese bis-phenoxy compound as flame retardants for poly(phenyleneoxide). Specifically, formulation No. 1 (the control) had a 0.I. of 25.5and UL 94 value of SB. In the even numbered formulations, the use of theparticular bis-phenoxy compound results ina significant increase in fireretardancy as measured by O.I. Formulation No. 1 had a SB rating, UL 94;however, the individual U.L. rating of SE-0 for most of theseformulations is, in this case, more indicative of increased flameretardancy.

The use of an enhancing agent such as Sb₂ O₃ to promote a cooperativeeffect between such agent and the bis-phenoxy compound is fullydemonstrated via the results obtained from testing the odd numberedformulations. The highest UL 94 ratings and significantly higher O.I.values are obtained by the use of an enhancing agent.

EXAMPLE II

Example I is repeated twice; once using a 10% bis-phenoxy compound leveland 3% Sb₂ O₃ level and secondly, 15% and 5% levels respectively. Atboth levels, the O.I. values and UL 94 ratings are slightly lower thanthe 20%/10% levels of Example I.

EXAMPLE III

Portions of the solid samples of Formulation Nos. 1-26 preparedaccording to the above described procedure of Example I are subjected tothe following ASTM tests in order to ascertain other properties of theresultant plastic composition:

    (1)  Tensile Strength                                                              (at break)       ASTM Test No. D638-61T;                                 (2)  Flexural Strength                                                                              ASTM Test No. D790-63;                                  (3)  Flexural Modulus ASTM Test No. D790-63;                                  (4)  Notched Izod Impact                                                                            ASTM Test No. D256-56; and                              (5)  Heat Distortion                                                               Temperature (HDT)                                                                              ASTM Test No. D648-56.                              

Each of the aforementioned ASTM Tests are standard tests in the art andare utilized collectively in order to ascertain the efficacy of apolymeric system as an overall flame retarded composition for commercialapplication. All of these ASTM Tests are to be considered asincorporated herein by reference.

The results of these ASTM tests show that the physical properties of thepresent invention compositions are basically the same (except O.I. andUL 94 values) as the plastic material without the flame retardant (i.e.formulation No. 1). Thus, there is no substantial adverse effect on thephysical properties of the plastic material when the novel compounds areincorporated therein.

EXAMPLE IV

The procedure of Examples I, II and III are repeated except that theenhancing agent used is zinc borate instead of Sb₂ O₃. Substantially thesame results are obtained using zinc borate as those obtained using Sb₂O₃. The other metal containing compounds are found to be equallyeffective.

EXAMPLE V

Samples of each of Formulation Nos. 1 through 26 Table II, are subjectedto temperature (thermal) stability tests via the use of thermalgravimetric analysis (TGA). This test employed the use of a "ThermalBalance", model TGS-1, Perkin-Elmer Corporation, Norwalk, Connecticutand an electrical balance, Cahn 2580 model, Cahn Instrument Company,Paramount, California. The results of these tests show that thebis-phenoxy compound containing Formulations had more than adequatestability for melt processing and subsequent heat aging (i.e. hightemperature applications) and thus demonstrating that the particularbis-phenoxy compounds are quite compatible with the plastic material.The bis-phenoxy compound stability thus aids in providing sufficientflame retardancy at the plastic decomposition temperature. This testalso demonstrates that these compounds do not exhibit migration.

In view of the foregoing Examples and remarks, it is seen that theplastic compositions, which incorporate these compounds, possesscharacteristics which have been unobtainable in the prior art. Thus, theuse of these compounds in the above described plastic material as flameretardants therefor is quite unique since it is not possible to predictthe effectiveness and functionality of any particular material in anypolymer system until it is actively undergone incorporation therein andthe resultant plastic compositon tested according to various ASTMStandards. Furthermore, it is necessary, in order to have commercialutility, that the resultant flame retarded plastic composition processcharacteristics such as being non-toxic. Use of these compounds in theplastic material has accomplished all of these objectives.

The above examples have been described in the foregoing specificationfor the purpose of illustration and not limitation. Many othermodifications and ramifications will naturally suggest themselves tothose skilled in the art based on this disclosure. These are intended tobe comprehended as within the scope of this invention.

What is claimed is:
 1. A plastic composition consisting essentially ofpoly(phenylene oxide) having incorporated therein an effective amount ofa flame retardant which is a compound having the formula:##SPC5##wherein Z is selected from the group consisting of bromine orchlorine; m and m' are integers having a value of 1-5; i and i' areintegers having a value of 0-2; HBCA is a halo-branched chain alkylenegroup having from 1 to 6 carbon atoms; and A is selected from the groupconsisting of cyano, nitro, lower alkoxy, lower alkyl, fluorine,dialkylamino, phenyl, halo-phenyl, benzyl and halo- benzyl, with theproviso that neither m + i nor m' + i' is greater than
 5. 2. Thecomposition as set forth in claim 1 wherein i and i' are both
 0. 3. Aplastic composition containing poly (phenylene oxide) havingincorporated therein an effective amount of a flame retardant which is acompound having the formula: ##SPC6##wherein Z is selected from thegroup consisting of bromine or chlorine; m and m' are integers having avalue of 1-4; i and i' are integers having a value of 1-2; HBCA is ahalo-branched chain alkylene group having from 1 to 6 carbon atoms, andA is selected from the group consisting of cyano, nitro, lower alkoxy,lower alkyl, fluorine, dialkylamino, phenyl, halo-phenyl, benzl andhalo-benzyl, with the proviso that neither m + i nor m' + i' is greaterthan
 5. 4. The composition as set forth in claim 3 wherein i and i' areboth
 2. 5. The composition as set forth in claim 3 wherein Z is bromineand A is cyano.
 6. The composition as set forth in claim 3 wherein Z isbromine and A is nitro.
 7. The composition as set forth in claim 3wherein Z is bromine and A is lower alkoxy.
 8. The composition as setforth in claim 3 wherein Z is bromine and A is lower alkyl.
 9. Thecomposition as set forth in claim 3 wherein Z is bromine and A isfluorine.
 10. The composition as set forth in claim 3 wherein Z isbromine and A is dialkylamino.
 11. The compositon as set forth in claim3 wherein Z is bromine and A is phenyl.
 12. The composition as set forthin claim 3 wherein Z is bromine and A is halo-phenyl.
 13. Thecomposition as set forth in claim 3 wherein Z is bromine and A isbenzyl.
 14. The composition as set forth in claim 3 wherein Z is bromineand A is halo-benzyl.